Ch. 11 Mandible, TMJ, and Sinuses

Question 1

how much skull rotation (from the lateral skull position) toward the IR is required with an axiolateral oblique projection for demonstrating the mentum region

Answer 1

45 degrees

Question 2

how much skull rotation (from the lateral skull position) toward the IR is required with an axiolateral oblique projection for demonstrating a general survey of the mandible

Answer 2

10-15 degrees

Question 3

specifically, where are the frontal sinuses located

Answer 3

between the inner and outer tables of the skull, posterior to the glabella

Question 4

if the area of interest is the temporomandibular fossae, what should the angle of the CR to the oml be for the AP axial (modified towne) projection to reduce superimposition of the temporomandibular fossae and mastoid portions of the temporal bone

Answer 4

40 degrees caudal

Question 5

aligning what plane to the IR prevents rotation of either a PA or an AP axial mandible

Answer 5

msp

Question 6

to avoid angling the CR for the erect PA (axial) caldwell sinus projection, the head should be adjusted so that the oml is how many degrees from horizontal

Answer 6

15 degrees

Question 7

what device provides inherent collimation during an orthopantomographic procedure

Answer 7

narrow, vertical slit diaphragm

Question 8

the axiolateral oblique projection of the TMJ is commonly referred to as what

Answer 8

modified law

Question 9

what specific positioning error has been committed if both sides of the mandible are superimposed with an axiolateral oblique projection

Answer 9

insufficient cephalic CT angle or skull tilt

Question 10

the frontal sinuses rarely become aerated before what age

Answer 10

6 years

Question 11

T/F - for a true PA projection of the mandibular body (if this is the area of interest) the AML should be perp to the IR

Answer 11

true

Question 12

where should the CR exit for a PA axial projection of the mandible

Answer 12

acanthion (at lips for PA projection)

Question 13

what must be done to prevent the ramus of the mandible from being superimposed over the c-spine with an axiolateral oblique projection of the mandible

Answer 13

extend the chin

Question 14

which specific aspect of the ethmoid bone contains the ethmoid sinuses

Answer 14

lateral masses of labyrinth

Question 15

which cranial line is placed parallel to the floor for orthopantomography of the mandible

Answer 15

IOML

Question 16

where are the petrous ridges on a well-positioned parietoacanthial projection

Answer 16

just below the maxillary sinuses

Question 17

to demonstrate any possible air or fluid levels within the paranasal sinuses, it is important to do these two things

Answer 17

• perform positions erect
• use a horizontal beam

Question 18

the oml forms what degree angle with the IR in the parieto-acantial (waters)

Answer 18

37 degrees

Question 19

if the patient cannot stand for the lateral projection of the paranasal sinuses, the projection should be taken how

Answer 19

horizontal beam

Question 20

T/F - MRI is the preferred modality to study soft tissue changes and masses within the paranasal sinuses

Answer 20

true

Question 21

what is the older term for the maxillary sinuses

Answer 21

antrum/antrum of highmore

Question 22

T/F - most CT studies of the paranasal sinuses do not require the use of contrast media

Answer 22

true

Question 23

which paranasal sinuses are demonstrated with an smv projection of the paranasal sinuses

Answer 23

sphenoid, ethmoid and maxillary

Question 24

T/F - the modified law method provides a bilateral and functional study of the TMJ

Answer 24

true

Question 25

the axiolateral oblique projection of the TMJ requires how much head rotation from lateral

Answer 25

15 degrees

Question 26

what is the drainage pathway for the paranasal sinuses called

Answer 26

osteomeatal complex

Question 27

which paranasal sinuses are projected through the oral cavity with the PA axial transoral projection

Answer 27

sphenoid sinuses

Question 28

what is the name of the passageway between the maxillary sinuses and the middle nasal meatus

Answer 28

infundibulum

Question 29

how much skull rotation (from the lateral skull position) toward the IR is required with an axiolateral oblique projection for demonstrating the body of the mandible

Answer 29

30 degrees

Question 30

a patient comes to the radiology department to rule out a possible polyp within the sphenoid sinus. what routine and/or special projection provides the best overall assessment of the paranasal sinuses for this patient

Answer 30

PA transoral projection in addition to routine 4

Question 31

what CR angle is required for the AP axial projection of the mandible if the ioml is perp to the IR

Answer 31

42 degree caudal

Question 32

what CR angle is required for the AP axial projection of the mandible if the oml is perp to the IR

Answer 32

35 degrees caudal

Question 33

what is the max CR angle needed for all of the axiolateral oblique projections

Answer 33

25 degrees cephalic

Question 34

a radiograph of a PA (Caldwell) projection for paranasal sinuses shows the petrous ridges are projected into the lower half of the orbits and are obscuring the ethmoid sinuses. the tech used a horizontal beam for the projection. the skull was positioned to place oml at a 15 degree angle from horizontal. what positioning modification is needed

Answer 34

head and neck to be extended more to project petrous ridges below ethmoid

Question 35

where is the CR centered for an AP axial projection of the mandible

Answer 35

1" superior to glabella

Question 36

which paranasal sinuses are best demonstrated with a PA (caldwell) projection

Answer 36

frontal and anterior ethmoid

Question 37

T/F - secondary osteomyelitis is often caused by tumor invasion

Answer 37

false

Question 38

which projection shows an inferosuperior view of sphenoid and ethmoid sinus

Answer 38

smv for sinuses

Question 39

which single projection for a paranasal sinus routine provides an image of all 4 sinus groups

Answer 39

lateral

Question 40

list the 4 most commonly performed routine projections for paranasal sinuses

Answer 40

- lateral - PA caldwell - parietoacanthial (waters) - smv

Question 41

which projection of the mandible projects opposite half of the mandible away from the side of interst

Answer 41

axiolateral oblique

Question 42

which imaging system provides a single, frontal perspective of the entire mandible

Answer 42

orthopantomography (panoramic tomography)

Question 43

the axiolateral oblique projection of the TMJ requires what CR angle

Answer 43

15 degree caudal

Question 44

which group of paranasal sinuses is best demonstrated with a parietoacanthial (waters) projection

Answer 44

maxillary sinuses

Question 45

a radiograph of a PA transoral projection shows the sphenoid sinus is superimposed over the upper teeth and the nasal cavity. how must the position be modified to avoid this problem during repeat

Answer 45

increase extension of head and neck to project entire sphenoid sinus through oral cavity

Question 46

which projection of the mandible demonstrates the entire mandible, including the coronoid and condyloid processes

Answer 46

smv

Question 47

which projection shows all 4 paranasal sinuses demonstrated

Answer 47

lateral

Question 48

which sinus is projected through the open mouth with a PA axial transoral projection

Answer 48

sphenoid sinus

Question 49

what position is most often use when performing a CT study of the sinuses

Answer 49

prone

Question 50

a radiograph of an axiolateral oblique projection of the mandible shows the body of the mandible is severely foreshortened. the body of the mandible is the area of interest, what positioning error led to this outcome

Answer 50

insufficient rotation of the skull toward the IR, skull should be rotated 30 degrees from lateral position

Question 51

where should the CR exit for both the PA parietoacanthial and PA transoral projections

Answer 51

level of acanthion

Question 52

how much skull rotation (from the lateral skull position) toward the IR is required with an axiolateral oblique for demonstrating the ramus region

Answer 52

0 degres - true lateral

Question 53

which cranial positioning line is placed perp to the IR for a PA or PA axial projection of the mandible

Answer 53

oml

Question 54

which projection shows the best view of maxillary sinuses

Answer 54

parietoacanthial

Question 55

the axiolateral (schuller) projection for the tmj requires a CR angle of what

Answer 55

25-30 degrees caudal

Question 56

which positioning line is placed perp to the IR for a parietoacanthial projection

Answer 56

mml

Question 57

which projection/method of the tmj requires that the skull be kept in a true lateral position

Answer 57

schuller

Question 58

what type of IR must be used with digital orthopantomography

Answer 58

digital detector/psp plate

Question 59

what kVp range should be used for paranasal sinus radiography

Answer 59

75-85

Question 60

T/F - ultrasound exams of the maxillary sinuses to rule out sinusitis are possible

Answer 60

true

Question 61

which projection shows the sphenoid sinus in oral cavity

Answer 61

PA transoral

Question 62

what is the one major difference in positioning between parietoacanthial and PA axial transoral projections

Answer 62

mouth is open with transoral

Question 63

T/F - the mandibular condyles move anteriorly as the mouth is opened

Answer 63

true

Question 64

which projection shows the best view of frontal and ethmoid sinuses

Answer 64

PA axial caldwell

Question 65

an infection of the teeth may travel upward and involve what sinus

Answer 65

maxillary

Question 66

T/F - the PA axial projection of the mandible produces an elongated view of the condyloid processes

Answer 66

true

Question 67

T/F - the CR should be angled 20-25 degrees caudal for the PA axial projection of the mandible

Answer 67

false - cephalad

Question 68

which aspect of the mandible is best visualized with an AP axial projection

Answer 68

condyloid process